Aim: To assess the diagnostic utility of an oral rinse active matrix metalloproteinase-8 (aMMP-8) point-of-care test (POCT) for differentiating periodontal health, gingivitis, as well as different stages and grades of periodontitis. Materials & Methods:The aMMP-8 index test was undertaken in 408 consecutive adults, followed by a full-mouth periodontal examination. The reference standard was the 2017 World Workshop classification of periodontal diseases. Sensitivity, specificity, and the area under the receiver operating characteristic curve (AUROC) were assessed.Results: 68.6% of the participants were diagnosed with periodontitis, including Stages I (15.9%), II (15.9%), III (29.7%) and IV (7.1%). A positive aMMP-8 POCT was associated with periodontitis after adjusting for age, gender, tobacco smoking and systemic diseases, while it was unable to differentiate among the stages/grades of periodontitis and between gingivitis/periodontal health. This test showed a sensitivity of 33.2% and a specificity of 93.0% for detecting periodontitis (threshold level >10 ng/ml). The levels of aMMP-8 adjusted by the number of teeth present (aMMP-8/NTP) performed better for periodontitis (sensitivity: 67.1%; specificity: 68.8%). Notably, aMMP-8/NTP were strongly predictive for Stage IV periodontitis (threshold level =0.4312 ng/ml) (sensitivity: 89.7%; specificity: 73.6%; and AUROC: 0.856). The test performance greatly improved in combination with age and smoking, with a sensitivity of 82.5%, a specificity of 84.4%, and an AUROC of 0.883. Conclusion:This aMMP-8 POCT is able to detect periodontitis with better specificity than sensitivity across the spectrum of its severity. This test may be useful for periodontal screening in conjunction with subject characteristics and/or other sensitive screening tools. Further validation studies are needed. K E Y W O R D Sdiagnosis, gingivitis, matrix metalloproteinase-8, periodontal health, periodontitis, point-ofcare test, screening, sensitivity and specificity Clinical RelevanceScientific rationale for the study: The traditional periodontal diagnostic approach relies on clinical parameters that are difficult to measure, lack precision to detect incipient periodontitis and can only reflect the previous tissue destruction. Point-of-care biomarker tests based on oral fluidsThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.

Aim: To clinically validate a self-reported questionnaire for periodontal disease and assess its accuracy for differentiating periodontal health and different stages of periodontitis.Methods: A Chinese (Cantonese) version of a self-reported questionnaire was prepared by translating and validating the original English questions proposed by the Centers for Disease Control and Prevention/American Academy of Periodontology (CDC/AAP). The utility of the CDC/AAP questionnaire and its individual questions was assessed against a full-mouth periodontal examination. Periodontal case definition was based on the 2017 World Workshop classification of periodontal diseases. Multivariable logistic regression and the area under the receiver operating characteristic curve (AUROC) analysis were performed to assess the accuracy of the questionnaire.Results: 408 subjects enrolled in this study, including those with periodontal health (16.2%), gingivitis (15.2%), Stages I/II periodontitis (31.8%) and Stages III/IV periodontitis (36.8%). Overall, the questionnaire had poor accuracy in detecting the presence of Stages I/II periodontitis with an AUROC 0.608. While it showed moderate to high accuracy for identifying periodontal disease (gingivitis and periodontitis), periodontitis and Stages III/IV periodontitis with an AUROC of 0.837, 0.803 and 0.870, respectively. Self-reported measures in combination with age and tobacco smoking showed excellent performance for identifying Stages III/IV periodontitis with a high AUROC of 0.953, a sensitivity of 95.7%, and a specificity of 89.0%. Specific questions and combinations provided greater utility to discriminate the various periodontal case definitions. Conclusions:The self-reported CDC/AAP questionnaire may be a feasible tool for detecting periodontitis, and its combination with demographic and lifestyle factors is useful for the identification of individuals with Stages III/IV periodontitis. This questionnaire seems less helpful in screening of Stages I/II periodontitis. Further studies are needed to test the validity in larger community-based populations.